Quick Answer
Short answer: Solar panel warranties typically account for shading damages by offering reduced power output guarantees, such as 80% or 90% of the rated power, depending on the amount and duration of shading. This allows for some flexibility in the warranty to account for real-world shading conditions.
Warranty Shading Calculations
Most commercial solar panel warranties use a set of standardized shading calculations to determine the impact of shading on system performance. The most common calculation is based on the “open circuit voltage” (Voc) of the panel, which is the voltage measured when no current is flowing. For example, a typical residential solar panel might have a Voc of 36.5 volts. The warranty might specify a maximum allowed reduction in Voc due to shading, such as 10% or 20%. If the shading causes a greater reduction in Voc, the warranty may be voided or the panel’s performance may be recalculated accordingly.
Shading Factors and Guarantees
Warranty shading calculations often take into account the type and density of shading, as well as the amount of time the shading occurs. For example, a warranty might guarantee 90% of the rated power output if the shading is intermittent (less than 1 hour per day) and 80% if the shading is continuous (more than 2 hours per day). The warranty might also specify a maximum allowed shading factor, such as 0.8 or 0.9, which represents the ratio of actual power output to rated power output under shaded conditions.
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